Inheriting no lease tenant whose paying below market

[Colton Crockett]

I am looking to purchase a duplex that I plan to house hack. The current tenants were family friends of the deceased owner. They are paying well below market value with no lease and would like to stay. My agent has suggested that we offer them the option to sign a lease prior to closing to ensure that there are no issues after closing. If they are unable to pay the increase what are the options for eviction? Is there a requirement for notice in PA for a non-lease tenant or can I make it part of my offer contingencies that they have to have the tenant vacated upon closing? Also, has anyone dealt with getting a tenant to sign a lease before closing actually occurs? I'm worried if that is even possible.